Institut für Radiologie, Medizinische Hochschule Hannover, Hannover, Germany.
J Magn Reson Imaging. 2011 Feb;33(2):328-39. doi: 10.1002/jmri.22443.
To increase the spatial coverage and to reduce slice crosstalk combined with an optimal signal-to-noise ratio (SNR) in 3D dynamic contrast-enhanced (DCE) magnetic resonance (MR) mammography.
Asymmetric sampling schemes and a new reconstruction strategy based on virtual coils are presented for density-weighted (DW) 3D imaging. Additionally, for MR mammography an alternating DW (ADW) sampling along the k(y) direction shifts the undersampling artifacts out of the signal reception region. Virtual coils for effective DW (VIDED) imaging suppresses the aliasing in undersampled DW imaging. VIDED and ADW were compared to the conventional Cartesian imaging in phantom and in vivo MR mammography studies.
The slice crosstalk was significantly reduced by VIDED and compared to Cartesian imaging the SNR increased by 16%. Additionally, VIDED and ADW provided a substantially increased field of view (FOV) in the slice direction and allowed the spatial resolution to be improved (up to 60% for ADW and 30% for VIDED) without lengthening the scan time.
VIDED and ADW improve the image quality in 3D DCE MR mammography by enhancing the spatial resolution, reducing the slice crosstalk at nearly optimal SNR, and increasing the FOV in the slice direction. For VIDED no lengthening of the scan time or usage of multichannel receiver coils is necessary.
在三维动态对比增强（DCE）磁共振（MR）乳腺成像中，提高空间覆盖范围，减少切片串扰，并结合最佳信噪比（SNR）。
针对密度加权（DW）3D 成像，提出了一种基于虚拟线圈的非对称采样方案和新的重建策略。此外，对于 MR 乳腺成像，沿 k(y) 方向的交替 DW（ADW）采样将欠采样伪影移出信号接收区域。用于有效 DW（VIDED）成像的虚拟线圈可抑制欠采样 DW 成像中的混叠。在体模和体内 MR 乳腺成像研究中，将 VIDED 和 ADW 与传统笛卡尔成像进行了比较。
VIDED 显著降低了切片串扰，与笛卡尔成像相比，SNR 提高了 16%。此外，VIDED 和 ADW 显著增加了切片方向上的视野（FOV），并允许提高空间分辨率（ADW 可达 60%，VIDED 可达 30%），而不会延长扫描时间。
VIDED 和 ADW 通过提高空间分辨率、在几乎最佳 SNR 下降低切片串扰以及增加切片方向上的 FOV，改善了三维 DCE MR 乳腺成像的图像质量。对于 VIDED，无需延长扫描时间或使用多通道接收线圈。
